larynx
voice box, contains vocal cords
trachea
windpipe, carries air to lungs
bronchi
2 branches from trachea, one to each lung
bronchioles
smaller airways inside lungs
alveoli
tiny air sacs were gas exchange occurs
lungs
organs containing alveoli
ribs
protects lungs
intercostal muscles
between ribs, help breathing
diaphragm
muscle below lungs, helps breathing
diaphragm
muscle below lungs; controls breathing
associated capillaries
blood vessels around alveoli for gas exchange
features of gas exchange
large surface area
thin surface
good blood supply
good ventilation
large surface area
many alveoli increase diffusion
thin surface
short diffusion distance
good blood supply
maintains conc gradient
good ventilation
fresh air keeps oxygen level high
inspired air
more oxygen
expired air
more CO2
more water vapour(air is humidifies in lungs)
limewater test
turns milky if CO2 is present
why inspired and expired air differ
Oxygen diffuses from alveoli → into blood ✔️
Carbon dioxide diffuses from blood → into alveoli ✔️
Air becomes warmer and more humid ✔️
effect of physical activity on breathing
rate increases
depth increases
why breathing increases
Muscles produce more carbon dioxide ✔️
Carbon dioxide is detected by the brain ✔️
Brain sends signals to increase breathing ✔️
More oxygen is taken in and CO₂ removed ✔️
